Tailoring of onboard system software

Tailoring of an operating system and an in embedded real-time operating system in particular is es-sential for both, kernel and operation. But many of current embedded real-time operating systems provide somebasic tailoring at the cost of depleting the flexibility of hardware, which causes the lack of flexibility, and de-grades their tailors. A layered modular tailoring model has been proposed together with some tailoring operationsto improve the flexibility of the systems, and algorithms have been proposed for verification of tailoring opera-tions with the current operating system.

Investigations of the mechanical response of dummy HTPB propellant grain under ultrahigh acceleration overload conditions using onboard flight-test measurements

In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measurement system were performed.Two projectiles containing dummy HTPB propellant grains were successfully recovered after the flight tests with an ultrahigh acceleration overload value of 8100 g.The onboard-measured time-resolved axial displacement,contact stress and overload values were successfully obtained and analysed.Uniaxial compression tests of the dummy HTPB propellant used in the gunlaunched tests were carried out at low and intermediate strain rates to characterize the propellant's dynamic properties.A linear viscoelastic constitutive model was employed and applied in finite-element simulations of the projectile-launching process.During the launch process,the dummy propellant grain exhibited large deformation due to the high acceleration overload,possibly leading to friction between the motor case and propellant grain.The calculated contact stress showed good agreement with the experimental results,though discrepancies in the overall displacement of the dummy propellant grain were observed.The dynamic mechanical response process of the dummy propellant grain was analysed in detail.The results can be used to estimate the structural integrity of the analysed dummy propellant grain during the gun-launch process.

Design of Central Management & Control Unit for Onboard High-Speed Data Handling System

The Main Optical Telescope (MOT) is an important payload of the Space Solar Telescope (SST) with various instruments and observation modes. Its real-time data handling and management and control tasks are arduous. Based on the advanced techniques of foreign countries, an improved structure of onboard data handling systems feasible for SST, is proposed. This article concentrated on the development of a Central Management & Control Unit (MCU) based on FPGA and DSP. Through reconfigurating the FPGA and DSP programs, the prototype could perform different tasks. Thus the inheritability of the whole system is improved. The completed dual-channel prototype proves that the system meets all requirements of the MOT. Its high reliability and safety features also meet the requirements under harsh conditions such as mine detection.

Omnidirectional Antenna Diversity System for High-Speed Onboard Communication

In this article,an omnidirectional dual-polarized antenna with synergetic electromagnetic and aerodynamic properties is propounded for high-speed diversity systems.The propounded antenna comprises a probe-fed cavity for horizontally polarized radiation and a microstrip-fed slot for vertical polarization.Double-layer metasurfaces are properly designed as artificial magnetic conductor boundaries with direct metal-mountable onboard installation and compact sizes.An attached wedge-shaped block is utilized for windage reduction in hydrodynamics.The propounded antenna is fabricated for design verification,and the experimental results agree well with the simulated ones.For vertical polarization,the operating bandwidth is in the range of 2.37–2.55 GHz,and the realized gain variation in the azimuthal radiation pattern is 3.67 decibels(dB).While an impedance bandwidth in the range of 2.45–2.47 GHz and a gain variation of 3.71 dB are also achieved for horizontal polarization.A port isolation more than 33 dB is obtained in a compact volume of 0.247λ_(0)×0.345λ_(0)×0.074λ_(0),whereλ_(0)represents the wavelength in vacuum at the center frequency,wherein the wedge-shaped block is included.The propounded diversity antenna has electromagnetic and aerodynamic merits,and exhibits an excellent potential for high-speed onboard communication.

服务天基感知业务的卫星互联网模拟验证系统设计与分析

提出具有遥感、星间星地组网、星载边缘计算功能的低轨卫星与地面云计算中心和天基、临近空间、空中、陆地、海面等各类型终端构成的卫星互联网总体架构,给出包括资源层、虚拟化层、服务层、服务管理层及应用层在内的星载边缘计算功能架构。针对星载计算能力有限、天基网络拓扑高动态等典型特征,在提出星载边缘计算模拟验证系统构建方法的基础上,设计服务天基感知业务的卫星互联网模拟验证系统,开展天基感知信息处理分发试验,并根据不同信息处理与分发方式对网络资源占用和用户服务时延的对比,分析不同能力条件下卫星互联网对天基感知业务服务的能力水平。

基于模型演化的列控车载设备组合测试案例重构方法

车载设备作为列控系统的关键设备之一,其测试需求在不断迭代。测试案例重构通过更新原有组合测试集覆盖变更的测试需求,实现对测试案例的高效重用,对生成演化后的测试集具有重要意义。根据车载设备输入模型的变化情况,提出一种基于模型演化的测试集重构方法。首先,通过比较演化前后组合模型的差异性,辨识出失效和新增的测试需求,并结合测试参数、参数取值、约束可能出现的演化情况分析两类测试需求的具体构成;其次,基于演化后的组合模型,依次采取修改、扩充、新增3个步骤重构原有测试集,修改不满足变更测试需求的原有案例,扩充新增参数取值,新增案例覆盖剩余测试需求;之后,根据约束间的相容性,将互不干扰的多条约束置于1条测试案例集中处理以精简测试集;最终,得到完备覆盖所有演化后测试需求的组合测试集。以车载设备模式转换等3种场景为例,对本方法进行了验证,研究结果表明:相较于现有方法,本方法能更充分地重用原有案例,测试集总体重合度提高了7.82%,后续人工修改测试案例文档的工作量相应减少,时间成本可降低18.26%。

GB/T 26990-2023《燃料电池电动汽车车载氢系统技术条件》标准分析

近年来随着燃料电池电动汽车技术不断升级,与35 MPa车载氢系统相比,公称压力为70 MPa的车载氢系统具有储氢体积密度大可提高整车续驶里程的优点,在乘用车上得到广泛应用。而在GB/T 26990—2011《燃料电池电动汽车车载氢系统技术条件》及GB/T 29126—2012《燃料电池电动汽车车载氢系统试验方法》中仅适用于公称工作压力不超过35 MPa的车载氢系统,而且该版标准已实施十余年,已不能完全适应现阶段燃料电池电动汽车车载氢系统技术现状,因此2023年11月,我国发布了GB/T 26990—2023《燃料电池电动汽车车载氢系统技术条件》,该标准修改和增加了部分技术内容以适应当前燃料电池电动汽车行业发展水平。本文将阐述GB/T 26990—2023的主要技术内容及其与上一版标准的异同,并对新标准中相关技术内容和测试方法进行解析,供行业内企业参考。

集成型车载充电系统并网模式模型预测控制策略

相较于传统车载充电系统,集成型车载充电系统(integrated onboard charger system,IOCS)在成本、功率密度等方面具备显著优势。文中基于六相永磁电驱系统设计了一台IOCS,并研究了模型预测电流控制(model predictive current control,MPCC)算法在该系统并网模式下的应用。首先,分析所提IOCS的电路拓扑并建立数学模型,同时介绍传统MPCC的实施流程。然后,针对传统MPCC计算量大、稳态性能差等不足,提出一种基于占空比优化的MPCC(MPCC based on duty cycle optimization,DCO-MPCC)策略。一方面,减少备选电压矢量数量,降低电流预测环节带来的计算负担;另一方面,提出一种占空比优化技术,改善系统稳态性能。最后,通过实验验证了所提算法的有效性与优越性。实验结果表明,DCO-MPCC策略能够显著提升系统稳态性能并减少算法计算量。充电与车网互动(vehicle to grid,V2G)工况下,网侧电流总谐波畸变(total harmonic distortion,THD)分别降低6.18%与5.92%,算法运行时间减少17.54μs。

基于分布式技术的动车组车载大数据存储与检索技术研究

随着动车组的数据传输能力升级改造以及复兴号智能型动车组的上线运营,动车组监测项点数据快速扩充,如何高效、准确地对动车组的海量车载非实时数据进行存储、检索与查询,成为提升动车组车载数据管理和应用水平面临的一个挑战。文中提出一种基于分布式技术的海量非实时数据地面系统架构,将各动车运用所的数据服务站点作为子节点,全路数据服务中心作为主节点,对具备时空属性的海量数据快速检索算法进行了研究,构建了一种支持分布式数据存储、检索及数据分析的架构,开发了原型系统,验证了解决方案的可行性和有效性。

燃料电池汽车车载氢系统潜在失效模式及原因分析

车载氢系统的安全性是燃料电池汽车(FCV)的核心技术指标之一,其安全性保障是实现FCV大规模商业化的重要前提。本文围绕车载氢系统的安全性,介绍了车载氢系统的组成,分析了车载氢系统及其零部件的失效模式及原因,总结了车载氢系统的失效后果,并探讨了现阶段在FCV消防安全方面亟需完善的内容。分析表明,车载氢系统的潜在失效模式及原因主要包括密封、振动疲劳、机械冲击、碰撞、快速充放氢疲劳、热损伤、控制系统功能失效等,失效的主要后果表现为氢气泄漏。对于氢气泄漏的危害分析应充分结合车辆所处的场景进行综合考量,在极端场景下,“氢气泄漏+密闭/半密闭空间+点火源”将引起火灾甚至爆炸,会严重威胁公众的生命财产安全。因此,建议从强化安全性设计和验证、提升氢泄漏监测和气源控制技术、开展失效致灾危害量化评价、加强火灾防控技术等多个方面,促进车载氢系统的安全性水平提升。

机载信息系统故障实时诊断功能的设计与实现

机载信息系统是飞机实现互联互通的重要系统,具有组成设备复杂且功能可扩展的特点。故障诊断功能为机载信息系统的基础功能之一,负责机载信息系统的健康监控。现阶段对机载信息系统的研究相对较少,且缺乏满足功能可扩展机载系统的故障诊断方法。基于机载信息系统功能可扩展的特点,设计了一种可配置故障的实时诊断方法。该方法不仅可以实现机载信息系统故障的实时诊断功能,并且可以满足系统功能可扩展性对故障诊断的要求。为验证所提出故障诊断方法的有效性,基于该方法设计了故障实时诊断软件,并在多个机型上验证了软件的有效性。

车载ATO系统记录板数据解析工具设计

为实现对列车记录数据的读取、解析与显示,便于数据分析和列控系统的后期维护,开发车载自动驾驶(Automatic Train Operation,ATO)系统记录板数据解析工具。在对车载ATO系统记录板数据解析工具需求规范进行深入分析的基础上,明确解析工具的各项具体功能,给出软件的总体设计思路及各功能的详细设计流程,最后介绍软件的使用方法,为后续用户使用提供指导。同时基于实测数据对软件功能进行测试验证。测试结果表明,所开发的解析工具可完全实现设计功能,且操作便捷。

一种轨道列车车载通信系统信息安全风险评估方法

提出一种基于通用漏洞评价系统(Common Vulnerability Scoring System,CVSS)的列车车载通信系统信息安全风险评估方法,详细介绍该方法的工作流程,开展缺陷概率评估、缺陷影响评估,得出各系统缺陷的风险范围所对应的信息安全等级,并最终应用到某国外地铁车载通信系统项目的信息安全风险评估活动中,为后续开展系统优化活动以及采取优化措施后的信息安全风险再定位奠定基础。

新型列控系统ATP车载设备开发过程安全控制措施研究

作为下一代列控系统的重要组成部分,新型列控ATP车载设备的设计开发需严格按照行业技术要求执行安全控制措施,以确保设备满足安全需求。从RAMS分析、系统测试、验证确认3个方面对设备开发过程中的安全控制措施展开研究:根据新型列控ATP车载设备的功能分析,采用Relex Studio建立可靠性框图及故障树模型,计算设备的RAMS等各指标符合技术条件要求;针对系统测试需求,设计测试流程,搭建仿真测试环境进行系统测试;通过具体验证活动与多种确认方法,验证新型列控ATP车载设备能够在目标环境中有效运行。新型列控ATP车载设备所采取的安全控制措施可提高其可靠性与安全性,为其他安全相关的铁路信号设备的设计开发提供参考。

引导式整车OBD自动核查系统的研究与应用

随着国六排放法规趋严,重型柴油发动机排放控制的车载诊断系统(Onboard Diagnostics,OBD)标定和策略也随之越来越复杂,为了确保汽车的安全、高效运行,对车辆进行OBD功能核查至关重要。现有整车OBD核查工作存在数据采集和处理不便的问题,同时主要依赖于专业工程师的经验和熟练程度,测试效率低,无法满足车型快速升级的需求。针对以上问题,提出了建立引导式整车OBD自动核查系统,基于Auto-Box控制盒,以OBD-II为基础,整合了多种技术手段,借助软件界面良好的人机交互性,实现引导式自动控制,实现了对车辆排放及性能状况的快速、准确检测和判断,从而提供了一套标准一致、流程规范的自动核查确认系统,辅助工程师进行核查确认,并最终达到替代专业工程师的目的。通过系统测试,证明了该系统具有较高的检测准确性和高效性,并且可以方便地应用于各种车型和环境,为汽车行业提供了一种安全、高效、低成本的整车OBD自动核查系统。

CTCS3-300H型列控车载设备状态在线监测与智能分析系统开发与应用

针对CTCS3-300H型列控车载设备(简称:列控车载设备)各单元运行日志数据分散存储、数据转储下载接口多、数据分析工作繁琐耗时的问题,根据列控车载设备结构特点,设计了列控车载设备状态在线监测及智能分析系统。该系统统一了列控车载设备各单元的日志数据采集与传输接口,借助既有的车地无线传输通道,设计了灵活、务实的车地数据传输方案,实现了用于列控车载设备状态在线监测的事件通告报文的实时传输,提供故障日志自动下载、手动按需下载两种日志数据无线下载方式,在满足列控车载设备状态在线监测和故障分析需要的前提下,最大限度地减少车地数据传输量。通过有效利用列控车载设备日志数据进行智能分析,能够快速、准确定位故障原因,实现故障自动报警并给出处置建议,提高了列控车载设备故障应急处置和维护效率,为动车组安全运行提供强有力的技术保障。

基于监测数据的ATP车载电台健康状态评估算法研究

在列车运行过程中,ATP车载电台运用不稳定会引起车地无线通信超时,导致CTCS-3级列控系统降级,影响列车运行效率。针对此类问题,通过研究电台多种常见故障及特征,设计一套用于ATP车载电台健康状态评估的算法。以接口监测数据、基站空口监测数据和车载空口监测数据为基础,通过学习与迭代,建立表征电台健康状态的模型作为评分基准;通过对比电台相关特征值与模型基准值,对各个电台进行健康状态评估。经验证,该算法可准确描述车载电台的健康状态,供运维人员对健康状态差的电台提前处理,从而实现电台故障的事前预防,对降低CTCS-3级列控系统无线通信超时概率、保障列车安全运行、提高铁路运维水平等具有重要意义。

基于CTCS-N列控系统的双电台冗余控制方法研究与设计

现有的CTCS列控系统大多采用单电台单连接方式实现与核心网的无线连接方案,不能有效保证无线连接的高可靠性和降低系统故障率。设计方案不仅可实现对CTCS列控系统双电台的冗余控制,当在用电台故障时,车载单元会自动选择备用电台重新建立与地面设备安全无线连接,从而保证列控系统的车载设备和地面设备无线通信快速恢复。而且在用电台可同时与多个设备建立多个安全无线连接,大大提高CTCS列控系统的安全性、可靠性、容错性。双电台切换过程虽有一定的时延,但对车载设备和地面设备的无线通信的影响较小。因此在列控系统的未来发展中,双电台冗余控制将成为未来新型列控系统的发展趋势。

Precise Orbit Determination for the FY-3C Satellite Using Onboard BDS and GPS Observations from 2013, 2015, and 2017

Using the FengYun-3C(FY-3C)onboard BeiDou Navigation Satellite System(BDS)and Global Positioning System(GPS)data from 2013 to 2017,this study investigates the performance and contribution of BDS to precise orbit determination(POD)for a low-Earth orbit(LEO).The overlap comparison result indicates that code bias correction of BDS can improve the POD accuracy by 12.4%.The multi-year averaged one-dimensional(1D)root mean square(RMS)of the overlapping orbit differences(OODs)for the GPS-only solution is 2.0,1.7,and 1.5 cm,respectively,during the 2013,2015,and 2017 periods.The 1D RMS for the BDS-only solution is 150.9,115.0,and 47.4 cm,respectively,during the 2013,2015,and 2017 periods,which is much worse than the GPS-only solution due to the regional system of BDS and the few BDS channels of the FY-3C receiver.For the BDS and GPS combined solution(also known as the GC combined solution),the averaged 1D RMS is 2.5,2.3,and 1.6 cm,respectively,in 2013,2015,and 2017,while the GC combined POD presents a significant accuracy improvement after the exclusion of geostationary Earth orbit(GEO)satellites.The main reason for the improvement seen after this exclusion is the unfavorable satellite tracking geometry and poor orbit accuracy of GEO satellites.The accuracy of BDS-only and GC combined solutions have gradually improved from 2013 to 2017,thanks to improvements in the accuracy of International GNSS Service(IGS)orbit and clock products in recent years,especially the availability of a high-frequency satellite clock product(30 s sampling interval)since 2015.Moreover,the GC POD(without GEO)was able to achieve slightly better accuracy than the GPS-only POD in 2017,indicating that the fusion of BDS and GPS observations can improve the accuracy of LEO POD.GC combined POD can significantly improve the reliability of LEO POD,simply due to system redundancy.An increased contribution of BDS to LEO POD can be expected with the launch of more BDS satellites and with further improvements in the accuracy of BDS satellite products in the near future.

Performance Evaluation of a Permanent Magnet Electric-Drive- Reconfigured Onboard Charger with Active Power Factor Correction

This paper presents a comprehensive charging operation for an electric-drive-reconfigured onboard charger(EDROC)with active power factor correction(APFC).The charging topology exclusively utilizes the three-phase permanent magnet synchronous motor(PMSM)propulsion system as a three-channel boost-type converter in which only a contactor and a small diode bridge are added.First,the operation scenario of the EDROC is introduced.Second,the relationship between electromagnetic torque and rotor position is investigated.Third,the current ripple cancellation of the EDROC is discussed in detail.Moreover,to implement the single-phase APFC along with charging voltage/current regulation of propulsion battery,control strategies including current balancing and synchronous/interleaving PWM strategies are incorporated.Finally,200W proof-of-concept prototype-based tests are conducted under different operation scenarios.